Using WRF-LES for Characterizing Entrainment of Turbulent Buoyant Plumes

Turbulent thermally driven buoyancy plumes have important applications in the atmosphere such as in wildfire plumes, volcanic plumes, and chemical plumes from anthropogenic sources. The purpose of the study is to propose a new model for entrainment of turbulent buoyant plumes within the convective atmospheric boundary layer. Previous entrainment models do not consider the background effects of a convective environment. Here we present a model that incorporates the factors of sensible heat flux and the atmospheric stability parameters into the entrainment model. An existing in-house WRF-LES- bPlume model with a two-way coupling between the ABL and the plume which was implemented within the Weather Research and Forecasting (WRF) Model was used. WRFLES-bPlume was used in two steps: I. Ambient Quasi-steady convective ABL was simulated, II. The plume was released within the ambient convective ABL and data collected for 2 hours. The cases of 1. Thermal plumes, 2. Heated buoyant plumes released from a large circular source (diameter -400m). in various unstably-stratified environments at geophysical scales have been investigated. The results are presented to quantity entrainment in terms of plume Reynolds number, Froude's number, non-dimensional surface heat flux and scaled Atmospheric stability parameters ( Richardson number and Monin-obhukov length scale).